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Design and Construction Modifications of Switched Reluctance Machines / Entwurf und konstruktive Modifikationen von Geschalteten ReluktanzmaschinenWichert, Torsten 25 February 2009 (has links) (PDF)
Although the design principles of the Switched Reluctance Machines (SRMs) are available in different fragments in numerous bibliography positions, there no exists the complex design procedure of whole drive system taking into account the SR Machine, control system and supply device as well. The hybrid design method for SRM drives with application of new analytical calculation methods, finite element method and simulation models is proposed in this thesis. The calculation/design system is characterised by important effectivity and reliability. The new possibilities in analytical determination of saturation effects and core losses under various modes of control, including sensorless method, are also taken into account. The correctness of the proposed design algorithms are verified by laboratory tests made on three motor prototypes manufactured in industry for concrete application. This dissertation provides the elements indispensable for more accurate and complex analysis and design of drives with switch reluctance motors. The elements of electrical motor and control system design as well as the considerations on the choice of supply device and controller subsystems are jointed in the thesis for final receiving of the design tool for considered industrial drive system.
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Polarisation dynamique nucléaire a basse température et fort champ magnétique pour des applications biomédicales en imagerie spectroscopique par résonance magnétiqueGoutailler, Florent 26 January 2011 (has links) (PDF)
Le travail de cette thèse a consisté à concevoir, réaliser et optimiser un montage expérimental de Polarisation Dynamique Nucléaire multi-échantillons pour des applications biomédicales en Imagerie Spectroscopique par Résonance Magnétique. Ce montage est constitué d'un aimant à fort champ magnétique (3,35T), dans lequel se place un système cryog&nique à bain d'hélium (He4) liquide pompé pouvant atteindre des températures infèrieures à 1,2K. Un ensemble d'inserts permet d'effectuer les différentes étapes du processus PDN dont l'irradiation des échantillons par un champ micro-onde (f=94GHz et P=50mW) et le suivi de leur polarisation par Résonance Magnétique Nucléaire. Ce système permet de polariser jusqu'à trois échantillons, de volume proche de 1mL, à des taux de polarisation de quelques pourcents. Il présente une forte autonomie supérieure à quatre heures, autorisant ainsi la polarisation de molécules à longues constantes de temps de polarisation. La possibilité de disposer quasi-simultanèment, après dissolution, de plusieurs échantillons fortement polarisés ouvre la voie à de nouvelles applications dans le domaine de l'imagerie biomédicale.
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Controlador PI FUZZY aplicado ao controle direto de potência do gerador de relutância variável de 12/8 conectado à rede elétricaCatata, Elmer Osman Hancco January 2016 (has links)
Orientador: Prof. Dr. José Luis Azcue Puma / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2016. / Este trabalho apresenta o controle direto de potencia do gerador de relutancia variavel de 12/8 utilizando o controlador fuzzy PI auto-ajustavel e o controle vetorial do inversor conectado à rede eletrica. Inicialmente são estudados os principios de operação da maquina e a topologia do conversor eletronico de potencia que sera utilizado para aciona-lo. Usando o software de simulaçãoMatlab/Simulink é implementado o modelo da maquina de relutancia variavel utilizando as curvas caracteristicas, de corrente e torque, que foram extraídas utilizando dados experimentais. Utilizando o modelo da maquina é projetado o controlador de velocidade para sua operação no modo motor. Tambem sera projetado o controlador de potência PI utilizando o modelo estimado do sistema de conversão de energia eólica.
A partir dos ganhos do controlador PI é projetado o controlador fuzzy PI autoajustavel com o objetivo de melhorar a resposta em regime permanente da potencia controlada. A potencia gerada pelo gerador de relutancia variavel é injetada à rede eletrica, atraves do controle independente das potencias ativa e reativa, para este proposito é utilizado um conversor trifasico de dois níveis. Na parte experimental deste trabalho foi implementado o controle de corrente por histerese para maquina operando no modo motor, posteriormente foi implementado o controle de corrente e controle da tens~ao no barramento CC para a máquina operando no modo gerador. Os resultados de simulação e experimentais se mostraram coerentes validando os controladores propostos. / This work presents the direct power control of the switched reluctance generator of 12/8 using the self-tuning fuzzy PI controller and the vector control for inverter connected to the grid. Initially, the machine's operating principles and the topology of the power electronics converter used to drive this machine are studied. The model of switched reluctance machine is implemented in Matlab/Simulink simulation software using the characteristic curves of current and torque extracted using experimental data. Using the machine's model, It is designed the speed controller for its operation in motor mode. Also, the PI controller is designed for the power control loop based on the estimation of the wind energy conversion system. Using the gains of the PI controller, It is designed the self-tuning fuzzy PI controller, in order to improve the steady state response of the power control loop. The power generated by the switched reluctance generator is injected into the power grid through the independent control of active and reactive power, for this purpose is used a three-phase two level converter. In the experimental part of this work was implemented the hysteresis current control for machine operating in motor mode, also, It was implemented the current and DC bus voltage control for the machine operating in generator mode. The simulation and experimental results were proved consistent and these results validate the proposed controllers.
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Estudo do gerador de relutância variável 12/8 conectado à rede elétrica aplicado em sistemas de geração eólicaOliveira, André Luiz de January 2017 (has links)
Orientador: Prof. Dr. Alfeu Joãozinho Sguarezi Filho / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2017. / Neste trabalho é estudado o gerador de relutância variável 12/8 aplicado em sistemas de geração eólica. Para a conexão do gerador com a rede elétrica será empregado o conversor em ponte assimétrico que compartilha o barramento de corrente contínua com um inversor. O conversor assimétrico tem a função de controlar a tensão no elo de corrente contínua e emprega controladores PIs para este fim. Já, o inversor conectado à rede elétrica controla as potências injetadas na rede por meio da técnica de controle orientado por tensão empregando controladores PIs. Analisou-se também as condições da máquina em termos de indução magnética através de simulações computacionais, pelo Método dos Elementos Finitos, com intuito de verificar e estimar os níveis de indução garantindo que a operação do controle atue de fato em condição de não saturação da máquina. Resultados das simulações de operação do gerador conectado à rede elétrica trifásica e dos níveis de indução magnética são apresentados para validar a proposta. / This academic work examines the switched reluctance generator 12/8 applied in wind power generation systems. A asymmetric bridge converter shares the DC link with an inverter that allows generator connection to the power grid. The asymmetric half bridge converter has the function of controlling the voltage of the DC link and uses PI controllers for this purpose. Already, the inverter connected to the grid controls the power injected into the grid across voltage oriented controle by employing PIs voltage controllers. It was also analyzed the machine conditions in terms of magnetic induction through computational simulations, by the Finite Element Method, in order to verify and estimate the induction levels, ensuring that the operation of the control actually acts in the condition of non-saturation of the machine. Results of the operation simulations of the generator connected to the three-phase electric grid and the magnetic induction levels are presented to validate the proposal
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台灣中小企業推動供應商關係管理策略與供應鏈績效關係之研究 -以防水連接器製造商H公司為例 / The relationship between the supplier relationship management strategy and supply chain performance in Taiwan’s SMEs: a case study of waterproof connector manufacturing company H陳詩敏, Chen, Shih-Min Unknown Date (has links)
在 JIT 以及全面品質管理(TQM)等新型生產流程思維出現之際,企業更 加強調供應鏈流程的優化及順暢,開始期望能透過建立供應商選擇機制、與供 應商協同製造合作、架設供應商間之資訊交流系統、形塑供應商評估學習體 系,進而減少供應鏈中無效率的浪費源頭,以降低供應鏈營運成本,提高利 潤。在這樣的環境背景下,供應商關係管理(SRM)儼然成為重要的供應鏈管 理手段,而供應商關係管理的效益也日漸備受重視。
本研究聚焦於目前因規模小、資金少、人員缺乏、可動用資源有限,故與 供應商之關係建立相對重要的台灣中小製造業,並選擇以藍海利基市場為發展 主軸之防水連接器製造商:H 公司為研究對象,以深度訪談之方式,探討其在 需求高度客製化、原材料須即時採購,即時組裝製造的環境下,如何經營其與 各供應商、協力廠間之關係,進而達成提升供應鏈效率的目標,而這樣的關係 經營行動對其供應鏈績效表現有何影響。研究結果發現,企業針對關鍵零組件 及關鍵原料之供應商,傾向建立長期合作之策略夥伴關係,而其採取之供應商 關係管理策略相較於對一般零組件及原料之供應商,更強調專屬性資產投入、 資訊流通共享、供應鏈協同合作之關係管理。反之,企業針對非關鍵零組件及 原料之供應商,較少有具體之供應商關係管理行動。其少數之關係管理行動主 要以降低買方之採購成本為目標,故管理方式大多僅限於維持高度例行性的合 作,或以價格為基礎評估、選擇合作對象。最後,針對供應商關係管理之實際 效益部分,本研究也發現,企業與供應商建立緊密關係,對供應鏈之內外面向 績效皆有正向影響,短期來說可改善生產力,長期而言則可加強競爭優勢。
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Modeling of Solar Radiation Management : A Comparison of Simulations using Reduced Solar Constant and Stratospheric AerosolsSirisha, K January 2014 (has links) (PDF)
The climatic effects of Solar Radiation Management (SRM) geoengineering have been often modeled by simply reducing the solar constant. This is most likely valid only for space sunshades and not for atmosphere and surface based SRM methods. In this thesis, a global climate model is used to test if the climate response to SRM by stratospheric aerosols and uniform solar constant reduction are similar. Our analysis shows that when global mean warming from a doubling of CO2 is nearly cancelled by both these methods, they are similar when important surface and tropospheric climate variables are considered. However, a difference of 1K in the global mean stratospheric (61-9.8 hPa) temperature is simulated between the two SRM methods. Further, while the global mean surface diffuse radiation increases by about 15- 20% and direct radiation decreases by about 8% in the case of sulphate aerosol SRM method, both direct and diffuse radiation decrease by similar fractional amounts (~ -1.5%) when solar constant is reduced. When CO2 fertilization effects from elevated CO2 concentration levels are removed, the contribution from shaded leaves to gross primary productivity (GPP) increases by 6 % in aerosol SRM because of increased diffuse light. However, this increase is almost offset by a 7% decline in sunlit contribution due to reduced direct light. Overall both the SRM simulations show similar decrease in GPP (~ 1%) and NPP (~ 0.7%). Based on our results we conclude that the climate states produced by a reduction in solar constant and addition of aerosols into the stratosphere can be considered almost similar except for two important aspects: stratospheric temperature change and the consequent implications for the dynamics and the chemistry of the stratosphere and the partitioning of direct versus diffuse radiation reaching the surface. Further, the likely dependence of global hydrological cycle response on aerosol particle size and the latitudinal and height distribution of aerosols is discussed.
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Impact of climate change on the snow covers and glaciers in the Upper Indus River basin and its consequences on the water reservoirs (Tarbela reservoir) – Pakistan / Impact du changement climatique sur les couvertures neigeuses et les glaciers dans le Haut Bassin de l'Indus et ses conséquences sur les ouvrages hydrauliques (Réservoir de Tarbela) – PakistanTahir, Adnan Ahmad 21 September 2011 (has links)
L'économie du Pakistan, fondée sur l'agriculture, est hautement dépendante de l'approvisionnement en eau issu de la fonte de la neige et des glaciers du Haut Bassin de l'Indus (UIB) qui s'étend sur les chaînes de l'Himalaya, du Karakoram et de l'Hindukush. Il est par conséquent essentiel pour la gestion des ressources en eau d'appréhender la dynamique de la cryosphère (neige et glace), ainsi que les régimes hydrologiques de cette région dans le contexte de scénarios de changement climatique. La base de données satellitaire du produit de couverture neigeuse MODIS MOD10A2 a été utilisée de mars 2000 à décembre 2009 pour analyser la dynamique du couvert neigeux de l'UIB. Les données journalières de débits à 13 stations hydrométriques et de précipitation et température à 18 postes météorologiques ont été exploitées sur des périodes variables selon les stations pour étudier le régime hydro-climatique de la région. Les analyses satellitaires de la couverture neigeuse et glaciaire suggèrent une très légère extension de la cryosphère au cours de la dernière décade (2000‒2009) en contradiction avec la rapide fonte des glaciers observée dans la plupart des régions du monde. Le modèle « Snowmelt Runoff » (SRM), associé aux produits neige du capteur MODIS a été utilisé avec succès pour simuler les débits journaliers et étudier les impacts du changement climatique sur ces débits dans les sous-bassins à contribution nivo-glaciaire de l'UIB. L'application de SRM pour différents scénarios futurs de changement climatique indique un doublement des débits pour le milieu du siècle actuel. La variation des écoulement de l'UIB, la capacité décroissante des réservoirs existants (barrage de Tarbela) à cause de la sédimentation, ainsi que la demande croissante pour les différents usages de l'eau, laissent penser que de nouveaux réservoirs sont à envisager pour stocker les écoulements d'été et répondre aux nécessités de l'irrigation, de la production hydro-électrique, de la prévention des crues et de l'alimentation en eau domestique. / Agriculture based economy of Pakistan is highly dependent on the snow and glacier melt water supplies from the Upper Indus River Basin (UIB), situated in the Himalaya, Karakoram and Hindukush ranges. It is therefore essential to understand the cryosphere (snow and ice) dynamics and hydrological regime of this area under changed climate scenarios, for water resource management. The MODIS MOD10A2 remote-sensing database of snow cover products from March 2000 to December 2009 was selected to analyse the snow cover dynamics in the UIB. A database of daily flows from 13 hydrometric stations and climate data (precipitation and temperature) from 18 gauging stations, over different time periods for different stations, was made available to investigate the hydro-climatological regime in the area. Analysis of remotely sensed cryosphere (snow and ice cover) data during the last decade (2000‒2009) suggest a rather slight expansion of cryosphere in the area in contrast to most of the regions in the world where glaciers are melting rapidly. The Snowmelt Runoff Model (SRM) integrated with MODIS remote-sensing snow cover products was successfully used to simulate the daily discharges and to study the climate change impact on these discharges in the snow and glacier fed sub-catchments of UIB. The application of the SRM under future climate change scenarios indicates a doubling of summer runoff until the middle of this century. This variation in the Upper Indus River flow, decreasing capacity of existing reservoirs (Tarbela Dam) by sedimentation and the increasing demand of water uses suggests that new reservoirs shall be planned for summer flow storage to meet with the needs of irrigation supply, increasing power generation demand, flood control and water supply.
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Design and Construction Modifications of Switched Reluctance MachinesWichert, Torsten 26 July 2008 (has links)
Although the design principles of the Switched Reluctance Machines (SRMs) are available in different fragments in numerous bibliography positions, there no exists the complex design procedure of whole drive system taking into account the SR Machine, control system and supply device as well. The hybrid design method for SRM drives with application of new analytical calculation methods, finite element method and simulation models is proposed in this thesis. The calculation/design system is characterised by important effectivity and reliability. The new possibilities in analytical determination of saturation effects and core losses under various modes of control, including sensorless method, are also taken into account. The correctness of the proposed design algorithms are verified by laboratory tests made on three motor prototypes manufactured in industry for concrete application. This dissertation provides the elements indispensable for more accurate and complex analysis and design of drives with switch reluctance motors. The elements of electrical motor and control system design as well as the considerations on the choice of supply device and controller subsystems are jointed in the thesis for final receiving of the design tool for considered industrial drive system.
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Non-Coupled and Mutually Coupled Switched Reluctance Machines for an E-Bike Traction Application: Pole Configurations, Design, and ComparisonHowey, Brock January 2018 (has links)
This dissertation contains a comprehensive analysis of both non-coupled and mutually coupled switched reluctance motors with concentrated windings for an electric bicycle traction application. Multiple pole configurations are analyzed and compared for each motor type. Includes magnetic design, thermal analysis, and structural analysis. A prototype is designed, manufactured, and validated. / This thesis discusses the design of both a conventional non-coupled
switched reluctance motor (CSRM) and a mutually-coupled SRM (MCSRM) for
an exterior rotor e-bike application. Several novel pole configurations were
analyzed for each machine type, and the performance of the final CSRM and
MCSRM designs were compared for this application.
A commercially available e-bike permanent magnet synchronous motor
(PMSM) was purchased, reverse engineered, and validated to define the geometry
constraints and performance targets for the designs. Since switched reluctance
motors do not use rare-earth permanent magnets, they are often seen as a potential
low-cost alternative to permanent magnet machines. The goal of this research is to
explain the relative advantages of CSRMs and MCSRMs when compared to PMSM
machines for a direct-drive e-bike application. The final CSRM and MCSRM
designs are analyzed in detail; electromagnetic, controls, thermal, and structural
considerations are all studied. A prototype of the final CSRM design was
manufactured and validated experimentally, using a dynamometer setup.
The finalized CSRM design is shown to be competitive with the PMSM
machine when considering torque output, and is superior in terms of peak
efficiency, and high speed torque performance. However, the CSRM noise output
and torque ripple were not compared to the PMSM, and a less-common
asymmetric-bridge converter is required for the CSRM, which may hinder the
ability for the machine to be implemented into existing e-bike packages.
The high speed torque performance of the MCSRM is shown to be inferior
to both the CSRM and PMSM, as is the torque quality and efficiency. The MCSRM
is shown to be highly resistant to saturation which gives it the potential for high
torque output at low speed (if thermal limits are not breached), though low
saturation levels also contribute to low machine power factor. The MCSRM may
be better suited to lower speed, high torque applications, for this reason. / Thesis / Doctor of Philosophy (PhD) / This thesis studies the design process and analysis of two different motor
types, for an electric bicycle application. They are designed to replace a
commercially available permanent magnet synchronous motor (PMSM). This type
of motor is typically expensive due to the rare-earth magnet material it requires.
The two motors discussed in this thesis are switched reluctance motors (SRMs),
which do not require magnet material, and thus have the potential to save cost (in
addition to other benefits). One of the SRMs has magnetic fields that are
independently controlled (CSRM), and one has fields that are controlled together
to produce torque (MCSRM). The magnetics, control, thermal, and structural
aspects of the CSRM and MCSRM are studied in detail. Novel geometry
considerations (i.e. novel pole configurations) which impact the magnetics of each
machine are compared to find the best-performing configuration for each machine
type.
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Position Sensorless Implementation for a Linear Switched Reluctance MachineMacCleery, Brian C. 17 June 2007 (has links)
The development of an add-on sensorless position estimator for a 4.8 m Linear Switched Reluctance Machine (LSRM) with minimal modifications to the transducer-based controller is investigated for the first time in this study. LSRMs require position feedback for closed-loop control but present a low cost, high energy efficiency alternative for linear actuation due to their rugged construction and single-sided excitation. Mechanical position transducers mounted on the vehicle are expensive and can impact reliability. The use of a sensorless position estimator removes all electronics from the passive vehicle, resulting in considerable reductions in cost, maintenance, and mechanical complexity.
This study examines the use of an add-on processor and data acquisition system for sensorless position estimation. An approach exploiting the active phase windings is used to preserve the normal operation of the transducer-based DSP controller with the goal of limiting reductions in high performance features such as force ripple reduction and velocity control [3]. The estimator system is retrofit to the transducer-based DSP controller by mimicking the output of a mechanical position sensor by emulating a Quadrature encoder. The feasibility and design issues for an add-on or retrofit position estimator are investigated. Although sensorless schemes for rotary Switched Reluctance Machines (SRMs) have been studied in detail, the problem of sensorless implementations for LSRMs has not been addressed. Experimental validation of the proposed sensorless estimation scheme is attempted, but closed-loop operation is not achieved successfully due to air gap fluctuations. In depth analysis of the sources and propagation of error is presented. / Master of Science
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